Hello everyone, I made a mistake for the last Email, the value of packet error rate should be 0.01. Here is a description of my question:
I add the link-error module in a simple link from node0 to node1(ns2.28 and ns2.33 both have this problem): ftp->tcp->node->link->node->tcpsink when I set the error rate bigger than 0.01, the first tcp packet(I think is syn) alsways have error and is dropped, the next transmission happened after 6 sec. Here is the trace file: packet error rate: 0.01 0.10000 0 0 1 0 t_seqno_ 1 0.14032 0 0 1 0 t_seqno_ 2 0.14032 0 0 1 0 t_seqno_ 3 0.18464 0 0 1 0 t_seqno_ 4 ... ... packet error rate: 0.02 0.10000 0 0 1 0 t_seqno_ 1 6.10000 0 0 1 0 t_seqno_ 0 6.10000 0 0 1 0 t_seqno_ 1 6.14032 0 0 1 0 t_seqno_ 2 Does anyone know the reason for this strange behavior? My tcl script is: set n0 [$ns node] set n1 [$ns node] $ns duplex-link $n0 $n1 2Mb 20ms DropTail set em [new ErrorModel] $em set rate_ 0.2 $em unit pkt $em ranvar [new RandomVariable/Uniform] $em drop-target [new Agent/Null] $ns link-lossmodel $em $n0 $n1 set tcp [new Agent/TCP] $ns attach-agent $n0 $tcp set sink [new Agent/TCPSink] $ns attach-agent $n1 $sink $ns connect $tcp $sink $tcp set fid_ 1 #Open the t_seqno_ trace file $tcp trace t_seqno_ set trace_ch [open "trace.txt" w] $tcp attach $trace_ch ... ... $ns at 0.1 "$ftp start" $ns at 63.5 "$ftp stop" Thank you very much for your help. Best Regards, Tong Mao
